FXUS63 KPAH 221521
AFDPAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
921 AM CST TUE DEC 22 2009
.UPDATE...
UPDATED TO REMOVE MENTION OF FREEZING FOG ADVISORY FROM BOTTOM OF
PRODUCT. FREEZING FOG IS NO LONGER A CONCERN...AS TEMPERATURES HAVE
ESCALATED ABOVE FREEZING IN MOST AREAS. AREAS OF FOG WILL SLOWLY
DIMINISH THROUGH THE NOON HOUR.
&&
.DISCUSSION...
IMMEDIATE CONCERN IS FOR AREAS OF FOGS THIS MORNING...WHICH MIGHT
DEPOSIT A THIN LAYER OF ICE...ESPECIALLY ON ELEVATED ROADWAYS ACROSS
THE REGION. TEMPS HAVE FALLEN TO NEAR OR BELOW FREEZING OVER MOST
AREAS...AND WILL GO AHEAD WITH A FREEZING FOG ADVISORY ALL LOCATIONS
THROUGH 15Z /9AM CDT/ TO COVER THIS CONCERN.
NEXT CONCERN IS FOR THE POTENTIAL FOR HEAVY RAINFALL OVER PORTIONS
OF THE REGION WED NIGHT INTO THU...ESP ALONG AND WEST OF THE MS
RIVER. IN FACT...AN AREA OF RAIN WILL LIKELY DEVELOP TONIGHT ALONG
A FRONTAL BOUNDARY THAT WILL SET UP OVER SRN PORTIONS OF THE
FORECAST AREA. THIS WILL BE IN RESPONSE TO 30-35 KT
MOIST/SOUTHERLY LOW LEVEL JET NOSING OVER THE FRONT...AND WEAK
ENERGY/H50 SHORT WAVE EJECTING OUT AHEAD OF THE MAIN STORM SYSTEM
OUT ALONG THE WEST COAST. THUS...WILL GO HIGH END POPS OVERNIGHT
WEST OF A MVN TO PAH LINE WHERE THE LOW LEVEL JET WILL BE MOST
PRONOUNCED.
AN EVEN STRONGER 40-50KT LOW LEVEL JET IS EXPECTED TO FORM WED
NIGHT OVER ABOUT THE WESTERN HALF OF THE FORECAST AREA AS THE MAIN
SYSTEM EJECTS NE OUT INTO THE PLAINS. A STRONGER SURFACE BOUNDARY
WILL ALSO BE APPROACHING SE MO BY LATE WED NIGHT INTO THU
MORNING...AND THIS LOOKS TO BE WHERE THE HEAVIEST RAINFALL
POTENTIAL WILL BE AT THAT TIME. WOULD NOT BE SURPRISED TO SEE A
COUPLE INCHES OF RAIN IN SE MO AND SW IL WED NIGHT INTO THU.
CONVECTIVE POTENTIAL WILL ALSO EXIST...BUT TRUE WARM SECTOR AIR
SHOULD REMAIN TO OUR SOUTH...SO SEVERE RISK SEEMS LIMITED AT THIS
TIME. BAND OF LOCALLY HEAVY RAINS WILL THEN SLOWLY TRAVERSE THE
REST OF THE REGION THURSDAY INTO THU EVENING. H85 WINDS REALLY
INCREASE /50-55 KTS/ AHEAD OF THE SFC FRONT THU...WITH GOOD
VERTICAL ALIGNMENT. WILL NEED TO MONITOR FOR POSSIBLE WIND
ADVISORY AS WINDS WILL LIKELY GUST AS LEAST 30 TO 40 MPH.
FRONT SHOULD BE EAST OF THE AREA BY MIDNIGHT THU NIGHT...AND RAIN
CHCS WILL FALL OFF DRASTICALLY FROM WEST TO EAST AS DRY SLOT MOVES
IN. CHRISTMAS NOW LOOKS COMPLETELY DRY MOST AREAS DUE TO THE DRY
SLOT AHEAD OF WRAP AROUND MOISTURE THAT WILL LIKELY MOVE BACK
INTO THE REGION FRI NIGHT/SAT TIME FRAME. HOWEVER...WINDS WILL
CONTINUE QUITE STRONG BEHIND THE FRONT AS THE SFC DEEP LOW MOVES
INTO THE WRN GREAT LAKES.
&&
.AVIATION...
WIDESPREAD LIFR CONDITIONS SET IN DURING THE PRE DAWN HOURS. LOWEST
CONDITIONS AT 12Z WERE IN KPAH/KCGI AREAS...WHERE CIGS WERE
VIRTUALLY ON THE GROUND. DUE TO THE LOWEST SUN ANGLE OF THE YEAR AT
ABOUT THE WINTER SOLSTICE...IT WILL BE A VERY SLOW PROCESS BURNING
THIS FOG OFF. WITH THE 12Z TAFS...THE TIMING OF IMPROVEMENT IN CIGS
AND VSBYS WAS DELAYED. ON THE FORTUNATE SIDE...TEMPS APPEAR WARM
ENOUGH THAT LITTLE IF ANY OF THE FOG IS FREEZING. ONCE THE LOW
CLOUDS DISAPPEAR...VFR CIGS ARE EXPECTED TONIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
MO...NONE.
IL...NONE.
IN...NONE.
&&
$$
